I was stripping off from my Emacs on Windows, every things I do not need
or use (or which is not design as I would like). But something does not
seems logical to me : as an example, I have removed the Allout package
(allout.el), Ok, but when I do a M-x TAB, allout-mode is still there
(and obviously fails if I hit ENTER, as I've removed it). I've run
search for allout inclusions in all *.el files, but this did not solve
the trick.

Yannick,
allout is probably still registered as an autoload.
Most of emacs's non-core functionality is provided by autoloaded functions.
An emacs autoload is where a function can be registered with emacs, but
not actually loaded.
When the function is first used in this instance of emacs, the defining
library is automatically loaded, and then the function is called as per usual.
This allows emacs to provide a lot of functionality without the memory and
start-up
over head of actually loading the function at start up.
What does C-h f allout-mode say?
If it is "allout-mode is an interactive autoloaded Lisp function in `allout'."
then it's an unloaded autoload, if its
"allout-mode is an interactive compiled Lisp function in `allout.el'."
then allout-mode has actually been loaded.
HTH,
Colin S. Miller
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